Technical Field
The present invention relates to a lane-line recognition apparatus.
Related Art
A known technique as disclosed in Japanese Patent Application Laid-Open Publication No. 1993-164569 is configured to extract edge points in an image ahead of a subject vehicle captured by a vehicle-mounted camera and recognize a lane line based on the extracted edge points.
Various types of lane lines include a broken line P1 as shown in FIG. 11. The broken line P1 includes alternating unit line segments P3 and missing sections P5 along a travel direction (a vertical direction in FIG. 11). The unit line segments P3 have a constant width and a finite length along a longitudinal direction and have a color (e.g., white, yellow or the like) different from that of a portion of a roadway surface other than the lane line while the missing sections P5 have a color similar to that of a portion of the roadway surface other than the lane line.
When extracting the edge points in a captured image including the broken line P1, not only the edge points P7 located at both side of each unit line segment P3 along the longitudinal direction, but also edge points P9 facing each missing section P5. A lateral position of each edge point P9 (a position in a direction perpendicular the travel direction of the roadway) is away from lateral positions of the edge points P7.
A lane line recognized as the broken line P1 should be a lane line P11 passing through only the edge points P7. However, the presence of the edge points P9 may prevent accurate recognition of the broken line.
In consideration of the foregoing, exemplary embodiments of the present invention are directed to providing a lane-line recognition apparatus capable of accurately recognizing lane lines including a broken line.